It estimates the aspect (i.e. the inclination angle of the gradient)
by considering a reference system which puts the zero towards the
north and the rotation angle anticlockwise. It differs from the drainage
directions in which it is given in radiants and it is a continuous function while drainage direction returns a number between 1 and 10. 

The aspect is 0 in the the North direction and increase clockwise.
The output map can be in degree or in radiants and there is also the possibility to round the results (useful especially if result is in degrees).
<br>
<br>
<h3>Inputs</h3>
<ul>      
<li>the file containing the matrix of the pitless elevations (as generated by the pitfiller module)</li>
</ul>
<br>
<br>
<h3>Output</h3>
<ul>      
<li>the file containing the aspect matrix</li> 
</ul>